Apparatus for treating liquids with gases



Oct. 23, 1923. 1,471,332

w. s. GREENAWALT APPARATUS FOR TREATING LIQUIDS WITH GASES Filed Sept. 26. 1921 3 Shun-Shoat 1 E I IE 3 -27 9 28 2 \z1 z 21 K26 1 z Ficl OOOOO zafl 21 21/ 5 24- Flcz /i//////////g//i{ INVENTOR Oct. 23 ,"1923.

w. E. GREENAWALT APPARATUS FOR TREATING BIQUIDS WITH GASES 3 Sheets-Sheet 2 Filed Sept. 26 1921 Tic 3 &

Oct. 23 1923.

W. E. GREENAWALT APPARATUS FOR TREATING LIQUIDS WITH GASES Filed Sept. 26. 1921 3 Sheets-Shut 3 Q H p u mm mm mm Oz. \5 3/2 FTC? INVENTOR mam Patented 0a. 23, 1923.

UNITED STATES WILLIAM E. GREENAWALT, OF DENVER, COLORADO.

APPARATUS FOR TREATING LIQUIDS WITH GASES.

Application filed September 26, 1921.

To all whom it may concern Be it known that 1, WILLIAM E. GREENA- WALT, a citizen of the United States. residing in the city and county of Denver and State of Colorado. have invented certain new and useful Improvements in Apparatus for Treating Liquids with Gases, of which the following is a specification.

The invention has for its more immediate object the effective atomization, or fine subdivision, of gas in liquids to accomplish certain results, as for example, the precipitation of metals from their solutions by a gas such as hydrogen sulphide, the application of sulphur dioxide to a. solution of iron salts to reduce the ferric iron to the ferrous condition, or the flotation treatment of certain ores. It is not intended to limit it to any particular use, although in describing the apparatus the above mentioned uses will be kept more or less in mind, and the description will be directed more particularly to the flotation treatment of ores.

This apparatus may be considered as a modification of the apparatus shown in my Patents No. 1,365,034, Jan. 11, 1921: No. 1,374,500, April 12, 1921: No. 1,350,605, Aug. 24, 1920: and No. 1,374,446, April 12, 1921. These patents disclose, in general, apparatus for atomizing gas in a liquid by means of a hollow rotary member submerged in the liquid: the gas being introduced into the interior of the'hollow rotary member independent of any mechanical connections, and ejected from the interior of the hollow rotary member through discharge passages into the surrounding liquid, in a fine state of subdivision.

In this apparatus it is intended to overcome certain defects in the apparatus above referred to, and to incorporate certain improvements and modifications which it is believed will give somewhat better results, at least under certain conditions of operation.

In describing the apparatus reference will be made to the accompanying drawings, in which Fig. 1 shows a longitudinal section through the apparatus, Fig. 2, the corresponding plan on the line 2-2 of Fig. 1; Fig. 3, a detail section through the rotary member, or atomizer; Fi 4, a. section on the line 4-4 of Fig. 3, wit a portion of the perforated or screen surface removed; Fig. 5, a cross section of two machines, back to back, with the one on the right somewhat modified from the one on the left which is Serial No. 503,463.

. the same as shown in Figs. 1 and 2; Figs. 6

and 7 are sections of modifications of the rotary member, or atomizer.

1n the drawings, 1 represents a tank, taken as a whole, containing the liquid and the material to be treated with the gas. The tank is preferably divided into compartments, or cells, 1", 1", and 1, and arranged so that the liquid passes successively through the different compartments. Air or gas is introduced into the compartments and into the rotary'atomizers through the gas inlet pipes 2. in the bottom of the tank. The compartments are also preferably divided into an upper and lower portion by a perforated partition 3, which may conveniently be perforated cast iron or sheet iron plates, made in sections so as to be easily inserted and removed. The upper portions of the compartments communicate with one another through the openings 4, and the lower portions through the openings 5. A complete apparatus may consist of one or of any convenient number of compartments. The liquid, or pulp, is flowed into the tank through the inlet 6, and overflows through the weir overflow 7. The lower outlet 8 is provided for matter in suspension which may be too heavy to pass over the weir overflow.

Suspended within the lower portion of the cells, by means of the shaft 9 and bearings 10, are the atomizers 12, which are rotated by means of the pulleys 11. These atomizers are preferably composed of a skeleton portion consisting of a hub 13. (see Figs. 3 and 4) a cylindrical peripheral wall 14, and radial arms 15. joining the hub with the periihe-ral wall. The peripheral wall portion is provided with openings, or discharge passages 16, formed by deflecting blades, or partitions, 17. These blades are preferably inclined, as shown, so as to create a positive flow of liquid and gas through the discharge passages and eject the liquid and gas into the surrounding liquid in the tank. The upper portion of each atomizer is preferably made of a number of screens 18 of various diameters, bolted to the hub 13 by means of the ring 19, and to the peripheral wall by means of the ring 20. The ring 20 also acts as a deflectorto give a slight upward movement of the gas and liquid discharged through the screens. The number of screens bolted to the top of the skeleton member will be determined principally by the desired degree ol atomization of the gas. 'l hesrrt' ens may he the ordinary trot'en wire t-loth or pet-titrated sheet metal. It is en dent. with on y one sheet ol sort-en. that the gas will not be as linely divided near the huh as toward the periphery. ditterenee in linear .-pet-t l, whit-h -ry largely determines the degree ot atointzntion. To eonipensate for the ditl'erenee 111 linear speed the screen may he made de:t--er or the perforations smaller toward the huh. This eti'ert is onveniently obtained by a selits of superimposed H'lttllS ot' gradually diminishing diameter toward th hill]. :1 shown by 1H". 1H". and th'. The screen? may be the ordinary wire mesh screening or pet'- forated metal lltll.2-l of regular manu l' rture. rut out in the form f an annulus, and bolted to the skeleton member as (lest-ribed. When one set of screens i worn out it may be tittiehlv and cheaply replaeedby another set The mesh of the st'reen will depend on the material to he treated and the resuits desired: line screens. espet-ially it" a number of them are superimposed. will gina liner atomization ol' the gas than t-oarstsever-a on the other hand. the speed of ro ation i--, quite as important a fat-tor in determining the degree of atomization as the lineness oi the sereens. l'nder ordinary ronditions, a strong wire or perforated sereen of model ate mesh will he used in eonneelion with moderate speed of rotation. In the llota- 'ion treatment of ores the mesh should be large enough to avoid clogging by the ore partirles.

Snrrotniding the atomizers are ballle Page 21. preferably set-tionally eonstrut'ttal. and supported from below. and consisoessentially of a lower ring 2; an upper IlllQ' :13. and radially disposed lmllles Z-l Minuet-ting the rings to form a t'tt; "lll(( strut-lure, supported by the lower ring, and lll'l'i lllltllllfl the rotary atoniizers. lhe hatlle cage is preferably t-onstrnt-ted in stt'ilUltw so that it. ran be ront'eniently inserted in the tank and removed therefrom without intewl'ennzn with the atomizer or shaft or being hatnpered by them. The ring :35 serves to hold the battle rage together and a t'tress 26 in the ott nt or the tank serves to keep it in plzt t'.

The gas is introdut-ed into the tank and into the atomizers through thetttlltltltll gas inlet :5. whieh (-onnet-t with the ttltll lll'l\-tll gas main :5. by means of the individual pipes .15 going to the various rolls. The tlow of gas is regulated by the valves 29. and the operator can immediately see the ell'et-t of varying aptantities of gas observing the snrl'at-e of the liquid. The llow of gas ean be regulated at will for th :lili'erent rolls. The gas need only he rompre -ed sutlieiently to (H'ltt'tlltlt' the statie head of the liquid: usually it need not be more than three or [our ounces for flotation (Hilltfl to the treatment of ores. The valves 30 are pro \ided to remove obstrtu-tions from the inlet pipe 2 should any oeeur. The method of introduein; the gas into the interior of the atomizer is immaterial, but. the method shown is preferred sint-e it is simple and admits of wide variation while the apparatus is in operation.

Fig. 4' shows a cross section of two cells. bark to bark. The cell. shown on the left, will he preferred in most cases since it pro tide for a simple circulation withoutany definite ehannel for return flow. If, howeyer. a definite circulation and return flow is desired, the arrangement, shown on the right. will give good results. The blades of the atomizers will give a positive eirt-ulation in either ease, and the degree of circulation will depend largely on the speed of rotation and the length and inclination of the blades. Ordinarily a violent circulation and agitation is to be avoided, but sufficient cirt'ttlalion should always be provided to avoid t-lo ging of the apparatus, in the treatment oi ore pulp and the like.

Fig. (i shows a modified atomizer, in that a srreen or perforated sheet 32 is bolted to the under side of the radial members 15. The radial members 17, without; a bottom slteel 32, tend to mix the gas and liquid het'ore the gas is ejected from the interior of the atomizer. preferred arrangement. If, howe er, a smooth surlaeeshould he preferred for the interior underside of the atomizer. it can he obtained by bolting a perforated metal sheet to the radial members. as shown. This ttrrangrement will enclose a portion of the liquid between the upper and lower screens, or perforated metal sheets. and this will tend to help subdivide the gas in passing through the upper portion of the atomizer.

Fig. 7 shows another tnoditit-ation of the atomizer. in that the screens are separated by annular rings 33. so that while the gas is passing from one sereen to the next through the intermediate liquid. there will he a tendeney also to furthersubdivide the gas and to ejt't'l the mixture of gas and liquid toward the periphery of the atomizer. in this lnodilit'aliolt. the. screens are preferably perforated metal sheets of Stlfilt'lttlt thieltness for the required strength and stability to maintain them in position when separated by the rings 32 This arrangement of the sort-ens will give a very good distribution of the atomized gas. especially in connection with the deliet'tor rin; 20. which also serves to hold the lower sereen in position, about the periphery of the atomizer.

The operation of the apparatus, in its applit'ation to flotation. may be briefly der't'liltttl as follows: The finely ]')ltl\l'iZL(l ore,- mixed with the desired amottnt of water and frothing agent to form a suitable pulp, is

Ordinarily this will be the I flowed into the tank through the inlet 6. The general stream of pulp will flow through the upper portion of the cells toward the weir overflow 7, but some of the heavier particles of ore will have a tendency to pass through the perforated plate 3 and enter the lower portion of the cells. The gas is introduced into the rotary atomizer in the amounts desired, as can be judged by looking at the surface of the pulp in the tank and noticing the effect with varying quantitles of the gas. The gas introduced into the interior of the atomizer, is ejected in a line state of subdivision mixed with a portion of the liquid, and is thoroly distrib uted in the liquid in the lower ortion of the cells. The atomized gas ascent through the perforated plate 3, into the relatively quiet upper portion of the cells, where the mineral particles are effectively floated toward the surface as a mineral froth. The froth overflows into a launder as shown in Fig. 5. It will be seen that the mineral, once floated. will have to sink against the current of ascending atomized gas to escape from one cell to the next through the openings 4 and through the weir overflow 7. The larger portion of the gangue descends to the lower portion of thecells, where it is kept in motion and gradually worked toward the outlet 8 in the lower portion of the last cell. A stream, somewhat less than the inflowing stream, is kept flowing through the outlet 8, while the weir overflow takes the difference and maintains a constant liquid level in the cells. The blades in the peripheral wall circulate the pulp, prevent the gangue particles from settling and packing, and serve to ipject streams of gas and pulp against the ba es, which still further subdivides the gas and! prevents too violent agitation of the in the lower portion of the cells.

pul T he battle-cage, which enclosed the atomwill be found to give good izer, also tends to distribute the atomized gas, so that the atomized gas is quite uniformly disseminated in the upper portion of the tank abovethe perforated plate.

The speed of rotation of the atomizer will depend largely on its diameter. With an atomizer from twelve to fifteen inches in diameter. a speed of from 250 to 450 R. P. M.

results. i

A relative slow movement may be used if the atomizer is made fairly large. If a large atomizer is used the top would be composed of a number of superimposed screens with their number increasing from the periphery toward the center of rotation. relatively slow movement of the atomizer would greatly help to subdivide the gas, distribute the subdivided gas in the liquid, and prevent settling of ore particles on the top of the atomizer. Under such conditions a relatively coarse wire fabric will give about the same results as a. fairly tightly woven The cloth fabric used in the ordinary stationary porous bottom flotation apparatus. The wire fabric will outwear many cloth fabrics and give a more uniform distribution of the atomized gas in the liquid in the tank.

The operation of the machine may continue indefinitely, or until some part is worn out. The perforated plates 3, as also t battle-cages 21. are preferably made in St tions so that they can be removed easily and quickly to get at the atomizcrs 12. The atomizers may also be easily removed from the shaft without removing the shaft from the bearin The idea would be to have extra atomizers and as the wire screens be come worn out, unscrew the atomizer from the shaft and immediately insert a new one, while the used one may be repaired at leisure.

I claim:

1. In apparatus for treating liquids with gases, a tank adapted to contain liquid. a rotary skeleton member suspended within the tank and submerged in the liquid. said rotary skeleton member being comprised of a hub attached, to the shaft. a peripheral cyl inder or ring and radial arms connecting the hub with the peripheral cylinder. a fluid permeable member attached to the hub and to the peripheral cylinder in removable relation thereto, and means for supplying gas to the interior of the tank through a submerged stationary gas inlet.

2. In apparatus for treating liquids with gases, a tank adapted to contain liquid, a rotary skeleton member suspended within the tank and submerged in the liquid, said rotary skeleton member beinp comprised of a hub attached to the shaft. a perforated peripheral c linder and radial arms connecting the cylin er to the hub. a fluid permeable member secured to the upper portion of the skeleton member in removable relation thereto, and a gas inlet in the lower portion of the tank arranged so that the gas in its ascent through the liquid in the tank will pass through the permeable member.

3. ln apparatus for treating liquids with gases. a tank adapted to contain liquid divided into compartments by vertical partitions arranged with communicating passages in their lower portions. hollow rotary members journalcd in the various compartments, bullies attached to a horizontal member Surrounding the respective rotary members and arranged so that lluid ejected. from the hollow rotary member of one compartment will pass between the batlles and through the communicating passages of the partitions into the adjoining compartment, and means for supplying gas to the interior of said rotary members.

4. In apparatus for treating liquids with gases. a tank adapted to contain liquid, a skeleton rotary member within the tank,

fiuid permeable members attached to the skeleton member in spaced relation and arranged to confine some of the liquid between them, and means for introducin gas into the tank and passing it through t e permeable members and the liquid enclosed by them and into the surrounding liquid in the tank.

5. In apparatus for treating liquids with gases, a tank adaptedto contain liquid, a skeleton rotary member suspended within the tank and submerged in the liquid, said Skeleton rotary member being open at the bottom and arranged with a removable top composed of a lurality of screens, and means for supplying gas to the interior of said rotary member.

6. In apparatus for treating liquids with gases, a tank adapted to contain liquid, a rotary member journaled within the tank, said rotary member having a plurality of perforated sheets of various diameters arranged about the rotating axis, and means for sup plying gas to the tank from a submerged inlet to rise through the perforated sheets of the rotary member in its ascent through the liquid in the tank.

I. In apparatus for treating liquids with gases, a tank adapted to contain liquid, a rotary member journaled within the tank, said rotary member having a number of perforated plates of various diameters arranged about the rotary axis and spaced apart, and means for supplying gas to the tank from a submerged inlet to pass through the rotary member in its ascent through the liquid in the tank.

8. In apparatus for treating liquids with gases, a tank adapted to contain liquid, a horizontal perforated partition within the tank dividing the tank into an upper and lower portion, a hollow circular rotary atomizer open at its bottom in the lower portion of the tank and adapted to eject fluid from its interior toward its exterior into the surrounding liquid, bafi'les supported from below arranged about the-rotary atomizer so as to allow fluid ejected by the atomizer to pass horizontally between the baflles, and means for supplying gas to the interior of the rotary atomizer.

t). In apparatus for treating liquids with gases, a tank comprising a series of compartments adapted to contain liquid, perforated horizontal partition dividing the compartments into upper and lower portions and having communicating passages between the compartments in both the upper and lower portions, rotary members in the lower portions adapted to subdivide gas in the liquid, and means for introducing gas into the lowerfortions of the compartments to be subdiv1 ed by the rotary members.

10. In apparatus for treating liquids with gases, a tank for containing liquid divided into compartments by vertical partitions, perforated horizontal plates dividing the compartments into upper and lower portions said lower portions of the compartments communicating with one another through openings in the vertical partitions, rotary members in the lower portion-of the compartments adapted to subdivide gas in the liquid, and means for introducing gas into the lower portion of the compartments to be subdivided by the rotary members.

11. In apparatus for treating liquids with gases, a tank adapted to contain liquid divided into compartments by vertical partitions, perforated horizontal plates dividing the compartments into upper and lower portions said lower portions of the compartments communicatin with One another through openings in t e vertical partitions, hollow rotary members in the lower portion of the compartments adapted to eject fluid from their interiors into the surrounding liquid, and means for introducing gas into the interior of said rotary members.

12. In apparatus for treating liquids with gases, a tank adapted to contain liquid, a rotary gas difl'using member journaled within the tank and submerged in the liquid, means for introducing gas into the lower portion of the tank to be atomized and diffused by the rotary gas diffusing member, and a baflie cage arranged about the rotary gas difl'usin member, said baflie cage being comprised o a horizontal member with vertically attached baflies arranged about the rotary gas diffusing member.

13. In apparatus for treating liquids with gases, a tank adapted to contain liquid, a rotary gas diffusing member journaled within the tank and submerged in the liquid, means for introducing gas into the lower portion of the tank to be atomized and diffused by the rotary gas difl'using member, and a baffle cage arranged concentrically with the peripheral circ e of the rotary gas diffusing member, said bafile cage being composed of upright bafiles resting on and attached to a horizontal member, said horizontal member being supported and maintained in place from below.

WILLIAM E. GREENAWALT. 

